Ture Falbe-Hansen, a spokesman for the Danish Energy Agency, told Russian news agency Tass the government was reviewing new plans submitted for the second leg of the gas pipeline running through the Baltic Sea to Germany.

"We have received the new application today and now we have to study it," he was quoted as saying.

The Danish Foreign Ministry is still considering the permits necessary to double the pipeline. The consortium managing the network is considering an alternate route through Danish waters, according to Tass.

Nord Stream AG, the pipeline consortium, had no public announcement regarding a revision to the Danish route.

Sweden's government issued the permit necessary for Gazprom to build and operate the 315 mile section of the planned second leg of the Nord Stream gas pipeline in its territorial waters in June. Russian energy company Gazprom is doubling the pipeline in order to add more capacity to the network's existing 760-mile artery.

Most of the Russian gas headed to the European market runs through Soviet-era pipelines in Ukraine. Political turmoil between Kiev and Moscow over gas arrears and later military conflict that followed Ukraine's pivot toward Europe exposed vulnerabilities to European energy security.

U.S. and European leaders, meanwhile, have considered liquefied natural gas sourced from American shale basins as an option to diversify the European energy sector. Russian Foreign Minister Sergei Lavrov said last year that European leaders in Brussels are getting duped into paying for "overpriced American liquefied natural gas," rather than piped gas from Russia.

"The growing exports of U.S. liquefied natural gas, if priced competitively, could play an increasing and strategic role in EU gas supply," European Commission President Jean-Claude Junckersaid Thursday.